DESCRIPTION: The patch-clamp technique is the central technique of modern cellular electrophysiology. It is used to obtain definitive information about gating and ion-transport mechanisms in ion channels and transporters, and provides a way in which ligands and modulators can be applied to these membrane proteins while their function is observed. The patch-clamp technique is also the premier single-molecule technique, where the stochastic behavior of a single ion channel can be observed directly. We propose to apply an exciting new discovery concerning electrode materials and fabrication techniques to greatly increase both the sensitivity and the ease with which patch-clamp recordings can be made. In the proposed work, we will apply microfabrication technologies to the refinement of a novel microelectrode technology based on poly (dimethylsiloxane). PDMS is a silicone polymer whose surface can be modified to form high-resistance seals with cell membranes; it can also be micromolded to very small feature sizes to form electrode apertures and the cellular interface for large arrays of patch-clamp electrodes. We propose to develop a very low-noise patch-clamp system based on the PDMS electrode technology, as well as electrode arrays to make possible the very simple "blind" patching of cultured cells. We also propose to incorporate microfluidic devices into the electrodes to allow for the first time the rapid exchange of the electrode solution. A substantial increase in sensitivity of this recording technique would open new areas of research as single-molecule events will be visible on much shorter time scales. The proposed simplification of the patch-clamp technique will have far-reaching benefits in the search for ion channel and transporter genes and in the discovery of new pharmacological agents.